Furnace grate



Dec. 4, 1923. 1,476,337 H. B. HOLT FURNACE GRATE Filed July 14 1922 6 5l I 30D 'I2 I ,f

il f um 73% 30 /3 FIELJE- /N VENTO/ #W f6. MP

Patented ec. 4, 1923.

unirse STATES Pariiznry orricn.

HARES B. HOLT, 0F DOR-MONT, PENNSYLVANIA, ASSIGNOR T0 ROSEDALE FOUNDRY t:MACHINE COIJPANY, F ETTSBURGH, PENNSYLVANIA, .A CORPGRATON OFPENNSYLVANIA.

FURNACE GRATE.

Application led July 14, 1922.

To all 'whom t may concern.'

Be it kno-wn that l, HARRIS B. Hoi-LT, residino' Dormont, .in the countyoi Alle gheny and State of Pennsylvania., a citizen ot the UnitedStates, have invented or discovered certain new und use'tul improvementsin vFurnace Gratos, of which improvements the following is aspecification.

My invention relates to furnace mates, and particularly to travellinggrates of the endless-chain type, which by their movement carry newsupplies of fuel to the urnace and carry away vthe ashes remaining aftercombustion. The objects of invention are simplicity of structure,durability, tacility in replacement, and efficiency.

ln the accompanying drawings Fig. I isa -tragmentary view oi a grate asseen from above, in which m invention is embodied; Figs. il and ll areviews in lon-k gitudinal and transverse section, on the planesrespectively indicated by the lines l'I-ll and IH-HL Fig. l; Fig. TV isa fragmentary section on the vertical plane indicated at IV-IV, Fig. I.-

The grate is made up ot a large number ot pieces of two kinds: links andgrate bars. The links are' of two particular shapes, indicated at l andl, They are elongate bodies, ordinarily iron castings, with provisionfor interpivoting, and to that end have in this instance transversepivot holes 12 at opposite ends. They are ifurther provided withintermediate outstanding essentially T-shaped lugs i3. Practically, lmake these links about seven and one quarter inches long and an inch andan eighth wide. The particular dimens sions are nnimpiiirtant beyondthis: they indicate how relatively small is 'he link compared with thedimensions ot the grate as a whole. Wide departure is ot coursepermissible from the dimensions given above by way of example. TheT-shaped lugs 18 are in links l about twice as wide as the body of thelinks-about two inches and a quarter wide, more or less. This greaterwidth of the lugs 18 is clearly shown in Figs. l and lll. Themodiiication in the lugs formed upon links l will presently be noted.

More minutely examined, these T-shaped lugs are transversely crooved orhollowed, as indicated at lll, and on either side verti- Serial N0.575,059.

cally grooved, as indicated at l5. To these minutite of comforinationattention will again be directed.

The multitude oi links is assembled and of adjacent rows areinterlocked, and the pivot pins imite the links row with row through theso interconnected ends. Thus the successive rows of links stand inechelon formation row upon row, while the whole articulated linkassembly has openings or meshes between the links, allowing passage ofair through the grate to the bed of fuel above.

lt is usual with chain grates to make the chain structure endless and tomount it on opposite sprocket wheels, by the turning of which thedesired grate ino-vement is attained. Such mounting and driving willordinarily be resorted to in the use of the grate 0In my invention, but,since these matters are of common knowledge, it suilices to make mentionof them, without illustration in the drawings.

l have Asaid that the T-shaped lugs 13 extending 'from the links aretwice as wide as the links themselves, and l have said that in assemblythe transversely aligned links stand the breadth of a link apart. Thelinks are assembled with these lugs standing out all from the same sideof the grate structure, the burden-sustaining side, and accordingly,when assembly has been made, the lugs of each row of links constitute ineffect a substantially continuous support, extending transversely fromside to side, across the articulated chain structure.

The marginal links are alternately of the forms l and la. Links l havealready been described. Links la differ in this respect only, that theirT-shaped lugs are built out laterally from the link bodies on one sideonly, as indicated at 13a, Figs. I and HT.

On the other side the lugs are ilush with the lateral face of the linkbody.

To the marginal links are bolted, midway of their length, blocks 5;these blocks form stops, to secure the grate bars when strung in lineupon the T-shaped cross rails, in the manner presently to be described.The marginal links 1fL are builtout with bosses 16 upon which block 5may be bolted. This last mentioned detail, shown in Fig. I, is moreclearly illustrated in `Fig. IV. y

The second component of the grate structure is theV grate bar. rhere isa large num ber of them, and they, but for the exception presently to benoted, are identicallyV alike.k They are essentially fuel-supportingplates 3, formed preferably iron castings, each provided underneath withtwo transversely extending convergent lugs 3l, defining and forming aseat for the Tshaped lugs 18 formed upon the links l.

The indi i lual grate bars may be of any desired width; convenientlythey are of equal width with the chain links, that is to say about aninch and an Dighth wide, and in assembly they are strung, one afteranother upon the transverse rails formed by the T-shaped lugs of thelinks, after the links themselves have been assembled. in the manneralready described.

The blocks 5 bolted to place secure the lines of grate bars whenapplied. The grate bars, then, like the links, are assembled, intransverse rows, but ordinarily they stand in'close succession, touchingone another, or substantially in contact. It is not important that thegrate bars of successive rows be aligned or be out of alignment;ordina.- rily -they will stand in alignment, or nearly so.

The drawings show certain more minute features of structure of thesegrate bar and these features I shall briefly note. These plate likegrate bars'are so formed that when assembled they overlap, in testudoformation, both transversely and longitudinally of the grate. Thetransverse Overlapping is illustrated in Fig. III, the longitudinal, inFII. This renement of shape will be understood without furtherelaboration; the reason for it is, while permittingthe passage of air,to prevent the sifting through of fuel and ashes, and also to screen thechain from the heat of the fire.

The noticeable convex arching of the up perk surfaces of the grate barsis afeature which makes for the easy discharge of the ashes. And thislast mentioned feature, t0- gether with the transverse corrugating ofthe burden-sustaining surfaces of the grate bars, facilitates theaeration of the bed of fuel, and aeration is of course essential tocombustion. The features also aid in the feed of fuel and of ashes. n

I have said of the grate bars that they may be of any desired width.Ifig. III shows marginal bars 3a of greater width than the medial barsof the 'transverse row. The reason for providing such wider niarginalbars is that a tendency to freer aeration of the bed of fuel along themargins is corrected anda more even burning achieved. Another reason isthat with wider marginal bars the whole grate moves more evenly. Thisprovision of wider marginal bars is not, however, a limiting feature,of` my invention as here embodied.

.Jair in suticient quantities for combustion has free access, throughthe interstices in the chai tliroughithe spaces e defined y and betweenthe grooved T-shaped extensions 13 formed on the links, and between theoverlapped'grate bars to the bed of fuel above. Aeration is facilitatedby the hollow spaces l), formed by and between the grooved tops of theT-shaped lugs 13 and the oppositel recessed under surfaces of the gratebars and by the spaces c between the grate bars, and aeration is furtherfacilitated by the arching of and the transverse corrugating of thecoal-sustaining upper surfaces of the grate bars.

The sifting through of dust and ashes which tends to foul such amechanism is by the testudo formation of the assembled grate barsprevented. The structure has a minimum number of parts and is .verysimple. The chain support is by the overlapped grate bars completelyscreened and protected from the heat of the nre. When a grate barrequiresrto be replaced, it may readily be slipped olf laterally and anew bar applied in place, without any greater disturbance of theorganized structure.

I claim as my invention:

l. In a chain grate structure a chain made up of rows of interpivotedlinks, the links being provided with lugs which in assembly combine andconstitute grate bar supports extending transversely across thestructure.

and a plurality of grate bars borne by said' supports in transverserows, the bars of each row standing in closed rank side by side.

2. In a grate structure al chain made up of rows of interpivoted links,the links being provided with lugs which in the assembly combine andconstitute grate bar supports extending transversely across thestructure, and a plurality of grate bars borne by said supports and eachgrate bar mounted upon and borne by one only of said supports.

In testimony whereof I have hereunto set my hand.

HARRIS B. HOLT.

Witnesses:

Fammi E. VVOLFF, PERGY A. ENGLrsH.

